Patent GB-992958-A (GB)
Title: Polypeptides and process for their manufacture
IPC: C07K14/68
Filed: 1961-07-28
Abstract: The invention comprises peptides of the formula L - seryl - L - tyrosyl - L - seryl - L-(X) - L - glutaminyl - L - histidyl - L - phenylalanyl - L - arginyl - L - tryptopyl - glycyl-L - lipyl - L - prolyl - L - valyl - glycyl - L - lipyl - L - lysyl - L - arginyl - L - arginyl - L - pioline in which X represents an acyl residue derived from an unsubstituted or a mercapto substituted, a C1-2-alkylmercapto, a sulphoxy-substituted or a sulpho-substituted a -C1-4-alkyl-a -aminoacetic acid and the peptides where the L-glutaminyl residue is replaced by the L-glutamyl residue, the esters, amides, hydrazides, N-acyl and amino protected derivatives and the acid addition salts thereof and a process for their preparation wherein the amino-acids L-serine, L-tyrosine, L-serine, L-(X)-OH, L-glutamine or L-glutamic acid, L-histidine, L-phenylalanine, L-arginine, L-tryptophane, glycine, L-lysine, L-proline, L-valine, glycine L-lysine, L-lysine, L-arginine, L-arginine, L-proline are linked together in the indicated order of succession by (a) reaction, in the presence of a condensing agent, of an amino acid molecule or peptide molecule in the form of an ester having a free amino group with another amino acid molecule or peptide molecule containing a protected amino group, or (b) reaction of an amino-acid ester or peptide ester having a free amino group with an amino acid or a peptide having an activated carboxyl group and a protected amino group, or (c) reaction of an amino acid or a peptide having a free carboxyl group and a protected amino group with an amino acid or a peptide having an activated amino group and a protected carboxyl group; and pharmaceutical compositions containing the polypeptides.  The residue X is preferably alanyl, valyl, leucyl, isoleucyl, a -aminobutyryl, cysteinyl, or methionyl or its sulphoxide or sulphone.  In the process it is preferred to form the nonadecapeptide either by condensing a deca- and a nona-peptide or tetra- and a penta-decapeptide.  Na  - Trityl - Ne  - tertiarybutyloxycarbonyl-L-lysyl - L - prolyl - L - valyl - glycine ethyl ester is prepared by tritylating the free amino peptide.  This compound is hydrolysed to the free acid and converted into Na -trityl-Ne -tertiarybutyloxycarbonyl - L - lysyl - L - prolyl-L - valyl - glycyl - (Ne  - tertiary - butoxy carbonyl)-L - lysyl - (Ne - tertiary - butyloxy carbonyl)-L - lysyl - nitro - L - arginyl - nitro - L - arginyl-L - proline tertiary butyl ester, and its free acid. The nonapeptide ester is selectively detritylated to the free amino peptide and the nitro groups reduced to give Ne  - tertiarybutyloxycarbonyl - L - lysyl - L - prolyl - L - valyl-glycyl - (Ne  - tertiarybutyloxycarbonyl) - L-lysly (Ne  - tertiarybutyloxycarbonyl) - L - lysyl - L - arginyl - L - arginyl - L - proline tertiary butyl ester acetate and tritosylate salts. The last-named nonapeptide is also prepared through either the Na -(p-phenylazo-benzyloxycarbonyl)-or Na -carbobenzyloxycarbonyl-nonapeptides in turn prepared by condensation of the appropriate tetra- and pentapeptides. Na  - carbobenzyloxy - Ne  - tertiary-butyloxycarbonyl - L - lysyl - L - prolyl - L - valyl - glycine is prepared from L-prolyl-L-valyl-glycine ethyl ester and the blocked L-lysine to give the tetrapeptide ethyl ester which is hydrolysed. Ne  - Tertiary-butyloxycarbonyl - L-lysine is prepared from L-lysine and either tertiarybutyl-phenyl carbonate or tertiary-butyl-p-nitraphenyl carbonate in the presence of "Amberlite" XE-64 (Registered Trade Mark) and is carbobenzoxylated to give the Na carbobenzyloxy - Ne  - tertiary - butylcarbonyl-L - lysine. Carbobenzoxy - L - glutamic acid-a -benzyl ester and iso butylene gave carbobenzoxy - a  - benzyl - g  - tert - butyl ester and this on hydrolysis gave carbobenzoxy-g -tert-butyl ester which was purified through the dicyclohexylamine salt.  Similarly is prepared the a  - ethyl - g  - tert - butyl ester.  The carbobenzoxy-g -tert-butyl ester was reacted with histidine methyl ester to give carbobenzoxy-(g -tert-butyl)-L - glutamyl - L - histadine methyl ester and then the free acid.  The ester is also converted into the hydrazide.  The free acid or the azide (prepared from the hydrazide) is condensed with L - phenylalanyl - nitro - L arginyl - L - tryptophyl-glycine methyl ester to give carbobenzoxy-(g  - tert - butyl) - L - glutamyl - L - histidyl - L-phenylalanyl - nitro - L - arginyl - L - tryptophylglycine methyl ester and the free acid and g  - tert - butyl - L - glutamyl - L - histidyl - L-phenylalanyl - L - arginyl - L - tryptophylglycine. The new foregoing hexapeptide and the nonapeptide were condened to give g -tert-butyl - L - glutamyl - L - hisitidyl - L - phenylalanyl - L - arginyl - L - tryptophyl - glycyl - (Ne -tert - butyl - oxycarbonyl) - L - lysyl - L - prolyl-L - valyl - glycyl - (Ne  - tert - butyloxycarbonyl)-L - lysyl - (Ne  - tert - butyloxycarbonyl) - L-lysyl - L - arginyl - L - arginyl - L - proline-tert butyl ester, through the Na -carbobenzyloxy derivative. Pharmaceutical compositions having MSH action comprise the nonadecapeptides of the invention in conjunction with or in admixture with a pharmaceutically suitable carrier.  The compositions may be in the form of tablets, dragees, ampoules, vials, powders, ointments, creams, suppositories, solutions, suspensions or emulsions, which may contain other therapeutically useful substances.  Specifications 872,332, 895,345, 957,892 and 992,957 are referred to.